Storage tank for liquids



Dee 4, 1928. 1,693,857

5. osER STORAGE TANK FOR LIQUIDS Filed 0:20.11. 1926 Patented Dec. 4, 1928.

UNITED STATES STUART MOSER, OF BERKELEY, GALIFORN OF CALIFORNIA, OF SAN FRANCISCO,

' WARE.

m, ASSI'GNOR 'ro STANDARD on. conrm camronma, A conrona'rron or DELA- S'IORAGE TANK FOR LIQUIDS.

Application filed December This invention relates to storage tanks for storing liquids, such as oil, and the invention is especially useful in connection with the type of tank in which the liquid is substantially covered by a floating-roof. One of the difliculties with this type of tank is that a considerable amount of evaporation occurs around the edge of the roof as it is not feasible to construct the roof to fit snugly Within the tank. It has been attempted to seal this annular space by means of packing but this has generally been unsatisfactory. The roofs have usually been constructed of a large circular deck with a flange around its edge. It is evident that such a roof will collect rain water, and if this rain water accumulates near one edge of the roof, as it usually does, it has a tendency to tilt the roof and may turn it over. For this reason, it is necessary to make some provision for carrying off the rain water accumulating on the roof. It is also necessary to exclude the rain water from the annular space between the roof and the tank wall and also to cover this space to prevent, or reduce as much as possible, the evaporation from it. In tanks of this kind, it is also advisable to provide simple means for supporting the floating roof of the tank if the level. of the liquid in the tank drops below a predetermined level. 7

The general object of this invention is to provide a tank construction which will meet these requirements as faras possible, which will have means for collecting the rain water at a point where it will not disturb the equilibrium of the roof, and from which point itcan be readily carried off from the tank; also to provide simple means for centering the roof in the tank, for excluding the rain water from the annular space around the roof and at the same time sealing, as far as possible, the liquid in the tank from evaporation. A further object of the invention is to provide simple means for supporting the floating roof, if the level of the liquid falls below a predeterm' ed point.

Further objects of the invention will appear hereinafter. V

The invention consists of the novel parts and combination of parts to be described hereinafter, all of which contribute to produce an eflicient storage tank for liquids.

A preferred embodiment of the invention is described in the following specification, while 11, 1926. Serial No. 154200.

the broad scope of the invention is pointed out in the appended claims.

In the drawing Figure 1 is a vertical section taken through a tank embodying my invention, a portion of the tank being broken away.

Figure 2 is a plan illustrating the means which I employ for supporting the floating roof on the bottom of the tank.

Figure 3 is a vertical section, through an apron, which I employ for sealing the annular space between the roof and the tank wall.

In the drawing 1 represents a storage tank .which is of cylindrical form, having a bottom 2 which rests on the earth and having a side wall 3.

The liquid 4 in this tank supports a floating roof 5, which is constructed of a large circular deck 6 provided with an upwardly extending cylindrical flange 7 which extends all around the edge of the roof. This deck 6 is constructed of thin plates, and it is constructed so that a depressed point is formed at a certain point on the deck. At this depressed point, I locate a sump to collect the rain water and I construct the deck in such a way that the water falling upon it will drain into this sump. I also provide piping, including a flexible connection, for carrying off the water from this sump to the exterior of the tank. In order to accomplish this, I prefer to construct the roof with a sump 8 disposed at its center, and I form the deck 6 with a plurality of depressed gutters 9 which extend radially inward. The inner ends of these gutters or channels 9 deliver the rain water through the cylindrical side wall of the sump 8. Between the channels 9, the deck is relatively elevated by reason of the ridges 10 or upwardly disposed convolutions of the plates which form the deck. At this relatively ele vated point gases escaping from the liquid will collect. For this reason, I provide an outlet at this point to permit these gases to pass out. This outlet is preferably an upwardly extending outlet pipe 11, provided with a bonnet 12 into which the outletadmits the gas, and this bonnet is surmounted by a check valve13 which opens upwardly and permits the gases to pass off without permitting air to enter. In order to carry off the water which may accumulate in the sump 8, I provide piping, including a radial pipe 14, which extends from the center of the tank out throu h the wall 3, and at the inner end of this ra ial pipe, I provide a flexible connection to the sump. This flexible connection annular space 21 between the edge of the roof and the tank. I provide an apron 22 of annular form. This apron may be constructed of asbestos reinforced by wire gauze, (see Figure 3). This apron is attached to the upper edge of the flange 7 of the roof and extends outwardly with its outeredge disposed near the wall of the tank or substantiallyagainst it. In order to center the roof in the tank, I provide a plurality of centering arms 23 which are in the form of outwardly bowed springs with the convex side of the bow disposed against the tank wall. These spring arms 23 are sufliciently resilient to enable them to pass readily over the rivets and seams of the tank. Apron 22 reduces evaporation through the space 21.

In order to brace the flange 7, I prefer to provide -a plurality of diagonal braces 24 which may be formed of light angle iron. The inner ends of the feet of these braces are attached to the deck 6.

In order to support the roof 5 clear of the tank bottom 2, in case the level of the liquid falls sufiiciently, I provide on the bottom 2 a plurality of stakes 25. These stakes are distributed substantially uniformly throughout the area of the bottom and they are braced in position by tie-wires 26 which are strung through openings near the upper ends of the stakes. The ends of these wires are anchored at 27 at the edge of the tank bottom.

In Figure 1, the upper side of the deck is represented as coinciding with the ridges or upward convolutions 10 of the deck and is represented as a level or horizontal line. However, when such a floating deck as this is in use, the upward pressure of the liquid on the bottom tends to produce an upward displacement of the bottom near the center of the roof and, hence the ridges 10 and the opening for the outlet pipe 11 will be slightly elevated above the outer edge 28 of'the deck.

In order to prevent the floating root from turning on its central axis so as to strain or twist oil the flexible joints at the pipes 15 and 16, I provide guiding means which may be in the form of two vertical guide bars 29 located on opposite sides of each spring arm 23. These guide bars engage the side edges of each spring.

The channels 9 are constructed so that they will always operate to carry off water to the sump. In this way they operate to prevent an accumulation of water at one edge of the roof which might depress the roof sufliciently to submerge the flange.

It is understood that the embodiment of the invention described herein is only one of the many embodiments this invention may take, and I do not wish to be limited in the practice of the invention, nor in the claims, to the particular embodiment set forth.

l/Vhat I claim is:

, 1. In a storage tank for liquids, thecombination of a tank, a floating roof supported on the liquidin the tank, having a deck with a flange extending upwardly around the edge of the deck, said deck having a depressed point with a sump located at the depressed point and having a plurality of channels formed in the deck operating to drain water to the sump and prevent an accumulation of water from tilting the roof suflicient-ly to submerge the flange, and an annular apron extending from the flange to the tank wall, excluding rain water and preventing evaporation of the liquid.

2. In a storage tank for liquids, the combination of a tank, a floating roof supported on the liquid in the tank, having a deck with a flange extending upwardly around the edge of the deck, said deck having a depressed point with a sump located at the depressed point, having a plurality of channels formed in the deck operating to drain water to the sump and prevent an accumulation of water from tilting the roof sufiioiently to submerge the flange, the flange covering the space between the flange and the tank, to exclude rain water and prevent evaporation from the liquid, and means for leading 011' the water that collects in the sump to the exterior of the tank.

3. In a. storage tank for liquids, the combination of a tank to contain the liquid, a floating roof supported on the liquid in the tank, having a substantially circular deck with an upwardly extending flange around the edge thereof, means ,for guiding the ed e of the roof on the tanklwall to maintain t e same centered in the tank, an apron carried by the flange extending outwardly, having its outer edge lying adjacent the wall of the tank to coverthe annular space between the flange and the tank wall, said deck having a depressed point with a sump located at the depressed point and having channels operating to collect water from the upper side of the deck into the said sump and prevent an accumulation of water from tilting the roof sufficiently to submerge the flange, and pip ing including a flexible connection with the sump, for leading the waater from the sump to the exterior of the tank.

4. In a storage tank for liquids, the combination of a tank, a floating roof supported an annular apron supported on i on the liquid in the tank, having a deck with a flange extending upwardly around the edge of the deck, said deck having a depressed point with a sump 'located at the depressed point and having a plurality of channels formed in the deck operating to drain water to the sump and prevent an accumulation of water from tilting the roof sufficiently to submerge the flange, said deck further having an outlet for gas accumulating under the deck and located at a relatively elevated point on the deck.

5. In a storage tank for liquids, the combination of a tank, a floating roof supported on the liquid in the tank, having a deck with a flange extending upwardly around the edge of the deck, said deck having a depressed point with a sump located at the depressed point and having a plurality of channels formed in the deck operating to drain water to the sump and prevent an accumulation of water from tilting the roof sufficiently to submerge the flange, said deck :turther having a valved outlet for gas accumulating under the deck and located at a relatively elevated point on the deck.

6. In a storage tank for liquids, the combination of a tank to contain the liquid, a floating roof supported on the liquid in the tank and having a deck depressed near its center, a sump adjacent the said center, said deck having a plurality of substantially radial channels formed therein operating to conduct rain water to the sump and prevent an accumulation of water from tilting the roof sufficiently to submerge the flange, piplng leading to the exterior of the tank and including a flexible connection to the sump to lead off the water collecting in the same, said deck having an upwardly extending flange around the edge thereof, centering arms carried by the flange for engaging the inner i'ace of the side Wall of the tank to maintain the roof centered in the tank,

and an annular apron at the upper edge of the flange extending outwardly with its outer edge disposed adjacent the wall of the tank, to substantially seal the annular space be tween the roof and the tank wall, and exclude the rain water.

7. In a storage tank for liquids, the combination of a tank, a floating roof supported on the liquid in the tank, having a deck with a flange extending upwardly around the edge of the deck, said deck having a depressed point with a sump located at the depressed point, with a plurality of channels formed in the deck for draining water to the sump, and a plurality of stakes distributed around on the bottom of the tank for supporting the roof when the level of the liquid drops sufliciently to permit the root to rest upon the stakes.

Signed at San Francisco, California, this 19th day of November, 1926.

STUART MOSER. 

